Direct Ink Write Printing of Chitin-Based Gel Fibers with Customizable Fibril Alignment, Porosity, and Mechanical Properties for Biomedical Applications

Abstract

A fine control over different dimensional scales is a challenging target for material science since it could grant control over many properties of the final material. In this study, we developed a multivariable additive manufacturing process, direct ink write printing, to control different architectural features from the nano- to the millimeter scale during extrusion. Chitin-based gel fibers with a water content of around 1500% were obtained extruding a polymeric solution of chitin into a counter solvent, water, inducing instant solidification of the material. A certain degree of fibrillar alignment was achieved basing on the shear stress induced by the nozzle. In this study we took into account a single variable, the nozzle’s internal diameter (NID). In fact, a positive correlation between NID, fibril alignment, and mechanical resistance was observed. A negative correlation with NID was observed with porosity, exposed surface, and lightly with water content. No correlation was observed with maximum elongation (~50%), and the scaffold’s excellent biocompatibility, which appeared unaltered. Overall, a single variable allowed a customization of different material features, which could be further tuned, adding control over other aspects of the synthetic process. Moreover, this manufacturing could be potentially applied to any polymer.

Bio‐Inspired Functional Materials for Environmental Applications

“…DIW also provides an additional benefit by overcoming challenges associated with traditional fabrication methods in the development of biological scaffolds that could be used as scaffolds for the templating of inorganic materials with multiple length scale features. [326,[343][344][345][346] For example, Kisailus et al have developed a one-step multivariable process for polymeric gel fiber production [347] that allows for the creation of scaffolds that mimic biological features with precise control of micro-and nano-architectural features, while also exhibiting biocompatibility (Figure 4.5a-d).…”

“…[ 326,343–346 ] For example, Kisailus et al. have developed a one‐step multivariable process for polymeric gel fiber production [ 347 ] that allows for the creation of scaffolds that mimic biological features with precise control of micro‐ and nano‐architectural features, while also exhibiting biocompatibility ( Figure a–d).…”

“…d) Optical microscope images of MCF‐7 cells grown in the presence or absence of the gels in a 48 well plate for 144 h. Reproduced with permission. [ 347 ] Copyright 2022, MDPI. e) Diagram of the electrically assisted 3D‐printing device.…”

“…b) Optical micrographs of the wet gel fibers andc) SEM micrographs of the entire fiber width (inset) and the surface. d) Optical microscope images of MCF-7 cells grown in the presence or absence of the gels in a 48 well plate for 144 h. Reproduced with permission [347]. Copyright 2022, MDPI.…”

Supramolecular Binding with Lectins: A New Route for Non-Covalent Functionalization of Polysaccharide Matrices

“…Indeed, there is a vast amount of literature available on this topic, which includes a wide range of fields, such as cosmetics, medicine, construction, water remediation, etc. [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Among these, chitin has received special attention for its high mechanical resistance, biocompatibility, biodegradability, crystallinity, mild antimicrobial activity, transparency, and abundance of highly-organized biogenic matrices [ 23 , 36 , 37 , 38 , 39 , 40 , 41 ].…”